Improved low temperature gold-gold bonding using nanoporous powder bump using vacuum ultraviolet irradiation pre-treatment

Tatsushi Kaneda, Jun Mizuno, Akiko Okada, Kaori Matsunaga, Shuichi Shoji, Mikiko Saito, Hiroshi Nishikawa

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Citations (Scopus)

Abstract

This paper describes a novel low temperature Au-Au bonding method using nanoporous Au-Ag powder and vacuum ultraviolet irradiation in the presence of oxygen gas (VUV/O<inf>3</inf>) pre-treatment. The nanoporous powder, which was fabricated by dealloying Ag-Au alloy sheet, was used to form the bump structure on the Au substrate by simple filing process, while an Au-coated Si substrate was used as the chip. The VUV/O<inf>3</inf> treated bumps and chip was bonded under a bonding pressure of 20 MPa at 200 °C for 20 min in a vacuum atmosphere of 1 kPa. A ligament size of the nanoporous structure on powder surface was found to be grown dramatically during bonding process. The tensile strength reached 10.1 MPa which is 2.3 times higher than that without VUV/O<inf>3</inf> treatment. This suggests that organic contaminants on the each ligament surface were effectively removed by VUV/O<inf>3</inf> treatment, and consequently, the diffusion of gold atoms in the nanoporous powder was significantly promoted to change into bulk structure. The proposed method will be highly a promising method for 3D-LSI and MEMS packaging.

Original languageEnglish
Title of host publicationICEP-IAAC 2015 - 2015 International Conference on Electronic Packaging and iMAPS All Asia Conference
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages473-477
Number of pages5
ISBN (Print)9784904090138
DOIs
Publication statusPublished - 2015 May 20
Event2015 International Conference on Electronic Packaging and iMAPS All Asia Conference, ICEP-IAAC 2015 - Kyoto, Japan
Duration: 2015 Apr 142015 Apr 17

Other

Other2015 International Conference on Electronic Packaging and iMAPS All Asia Conference, ICEP-IAAC 2015
CountryJapan
CityKyoto
Period15/4/1415/4/17

Keywords

  • Flip chip bonding
  • low temperature bonding
  • nanoporous powder
  • VUV/O<inf>3</inf> treatment

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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    Kaneda, T., Mizuno, J., Okada, A., Matsunaga, K., Shoji, S., Saito, M., & Nishikawa, H. (2015). Improved low temperature gold-gold bonding using nanoporous powder bump using vacuum ultraviolet irradiation pre-treatment. In ICEP-IAAC 2015 - 2015 International Conference on Electronic Packaging and iMAPS All Asia Conference (pp. 473-477). [7111061] Institute of Electrical and Electronics Engineers Inc.. https://doi.org/10.1109/ICEP-IAAC.2015.7111061